Nail & Screw Quantity Calculator
Estimate the fasteners for a job from the number of joints and fasteners per joint — total count, boxes to buy and cost.
How it works
total = ceil( connections × fasteners per connection × (1 + waste%) ) · boxes = ceil(total ÷ box count)
Fastener counts scale with the number of connections and how many fasteners each one takes, plus a margin for dropped, bent and countersunk-then-removed fasteners. Deck boards take about 4 screws per joist crossing, framing studs 2–3 nails per end, and sheathing follows a nailing schedule around the edges and field. Divide the padded total by the box count to know how many boxes to buy.
Worked example
A deck with 50 boards crossing 4 joists is 200 connections at 4 screws each = 800 screws. Add 10% for drops → 880, and at 500 per box that is 2 boxes. At $28 a box, $56 in screws.
Frequently asked questions
How many screws per deck board?
Two screws at every joist the board crosses — so a board over 4 joists takes 8 screws. Estimate total screws as boards × joists crossed × 2, then add about 10% for drops and mis-drives.
What fastener should I use outdoors?
Use hot-dip galvanized or stainless steel outdoors, and fasteners specifically rated for ACQ/treated lumber — the copper in modern treatment corrodes plain steel fast. Matching the fastener to the wood and exposure matters more than the count.
How much extra should I buy?
About 10% over the calculated need for general work, more if you are toe-nailing or working overhead where drops are common. Fasteners store forever, so rounding up to a full box is rarely wasted.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.